The invention relates to a multicomponent composition for filling and/or injecting cracks, flaws and cavities in structures or earth and rock formations.
Various types of materials are known for filling and/or injecting cracks, flaws and cavities in structures or earth and rock formations to prevent the penetration of moisture. In particular, sealants based on polyurethanes, epoxy resins and (meth)acrylates and based on cement are used. These sealants each have a very independent spectrum of properties, with the result that they are used for different filling or injection purposes. These material properties are divided into three groups according to the European standard EN 1504, Part 5 “Injection of concrete components”. A first group comprises the friction-bonding sealants, a second group comprises the expandable sealants and a third group comprises the swellable sealants.
The first group of friction-bonding sealants includes epoxy resins and cementitious sealants. The second group of expandable sealants includes the polyurethanes and the third group of swellable sealants includes the poly(meth)acrylates.
Owing to their high cost-efficiency, cementitious sealants of the first group are frequently used for filling relatively large cavities, such as, for example, ridge injections. For fillings providing a seal, however, these cementitious materials are suitable only to a limited extent since, in the case of water-carrying flaws, they would be washed out before hardening. Furthermore, owing to the filling with friction bonding, there is the danger that the filled flaws will break open again when the components are subjected to loads.
In contrast to cementitious sealants, sealants based on organic materials, such as, for example, polyurethanes or poly(meth)acrylates, have very broad reaction behavior which can be substantially influenced according to the chemical nature of the sealant. Thus, in particular the curing time of the composition can be adjusted in a very variable manner in a range from a few seconds to several hours by means of accelerating substances, such as, for example, catalysts. Furthermore, it is possible to prepare sealants which, owing to their flexible properties, absorb movements within the filled body up to a certain extent without damage. However, the higher material costs are disadvantageous in the case of the sealants based on organic materials. In the case of customary epoxy resins and polyurethanes, organic solvents are moreover required for cleaning the equipment necessary in the processing and in the application. This in turn is less economical and should rather be considered problematic from the environmental point of view since the solvents have to be disposed of after their use for cleaning. Water-based systems, such as typically poly(meth)acrylate systems or specific hydrophilic polyurethanes (polyurethane gels), prove to be less problematic from the ecological point of view but, owing to their swelling behavior, are associated with a rather low pH in the discussion regarding a possible danger of corrosion for reinforcing steel in reinforced concrete structures.
It is also known that cementitious materials as sealants can be mixed in the non-set state with plastic dispersions in order positively to influence the flow, solidification and processing properties of the still flowable sealant. At high concentrations of such plastic dispersions in the non-set sealant, however, the proportion of plastic has an effect which is not negligible in the hardened state, for example on the hardness, the porosity and the density.
When selecting the sealants, the choice is limited to the combination of the properties of the individual constituents in the unhardened and in the hardened state. It would be desirable if the properties of the abovementioned sealants of the three different groups according to EN 1504 could be freely combined.